The lateral load resistance behavior of single-shear unconstrained metal-to-parallel bamboo strand panel (PBSP) single-bolt connections was investigated. The connection consisted of a PBSP main member fastened to a metal plate as a side member using a 6-mm diameter bolt without a nut or washer used. The mechanics-based approach was used to evaluate critical factors on the lateral load resistance performance of metal-to-PBSP single-bolt connections. Experimental results indicated that the lateral resistance loads of the metal-to-PBSP single-bolt connections were significantly affected by its shear strength parallel to bamboo strand orientation, tensile strength perpendicular to bamboo strand orientation, and bolt-bearing strength in PSBPs. Lower tensile strength perpendicular to bamboo strand orientation of PBSPs can limit its usage as connection members resisting lateral loads. The proposed mechanical model was verified experimentally as a valid means for deriving estimation equations of lateral resistance loads of unconstrained metal-to-PBSP single-bolt connections evaluated in this study.